Growth variability of farm grown teak in response to climatic and soil factors across three agroclimatic zones of Tamil Nadu, India

Teak (Tectona grandis, Linn. f) is a prized hardwood species with remarkable properties that make it a favored material in various industries. In current trend, the cultivation of teak in farmlands is considered as a promising option. But the documentation and research on growth attributes and the studies on influence of climatic and edaphic factors on growth of teak raised in farmland condition is lacking. In this regard, the present investigation on farm grown teak was perpetrated in three agroclimatic zones viz., High Rainfall Zone, Southern Zone and Cauvery Delta Zone of Tamil Nadu in four different age classes (0-5, 5-10, 10-15 and 15-20 years). The study was carried forward with the prime motive of determining growth attributes and analyzing the impact of climatic and edaphic parameters on growth biometry of farm raised teak, both in block and boundary plantations. The soil physico-chemical parameters were analyzed both in surface (0-15 cm) and subsurface (15-30 cm) of plantations and the outcomes were presented in the form of cluster heat map, the results revealed that maximum organic carbon (0.62%), available nitrogen (197 kg ha^-1), available phosphorous (22 kg ha^-1), available potassium (340 kg ha^-1), bulk density (1.34 g/cm³) and porosity (51.10%) were observed in surface soils of high rainfall zone. The follow-up of correlation studies between growth and climatic variables using R-software brought to light that tree volume positively correlated with climatic parameters viz., annual rainfall, mean minimum temperature and mean relative humidity, but showed negative correlation with respect to mean maximum temperature in both boundary and block plantations. Harmoniously, the correlation analysis between growth and edaphic parameters showed positive correlation with edaphic variables viz., organic carbon, available nitrogen, available phosphorous and available potassium, whereas growth depicted negative correlation with pH and electrical conductivity in both boundary and block plantations. In addition, principal component analysis was carried out to determine the most contributing factor among all and also to portray the highly suitable zone for teak cultivation. The overall study results portray that among climatic parameters, annual rainfall has significant impact on growth of teak and with respect to edaphic variables organic carbon play a crucial role in improving the growth of teak raised in farm settings. In regard to various zones surveyed, High Rainfall Zone exhibit favorable climatic and soil conditions, which in turn reflect better growth performance when compared to other zones taken into consideration.